Could You Outrun a Hungry Tyrannosaur?

By Jon Tennant | January 28, 2016 12:43 pm

(Credit: Rod Beverley/Shutterstock)

One question has always burned in the minds of paleontologists: If Tyrannosaurus rex was still around today, would it be able to catch and eat you?

The problem stems from our ability to accurately reconstruct the speed of extinct animals when all you have to go off are their bones. Trying to figure out where all the muscles went and the forces exerted by them during sprints, especially with dinosaurs, is no easy task.

Trackways, a series of foot impressions, are key evidence in speed investigations, as scientists can use footprints to work out how fast an animal was traveling when they made the tracks. Unfortunately, T. rex trackways are notoriously rare. But under the guidance of University of Alberta paleontologist Scott Pearsons, three trackways were recently discovered on the surface of an ancient, dried up riverbed — known as the Lance Formation — in Glenrock, Wyoming.

Sprinter or Slouch?


The 66-million-year-old footprints of a tyrannosaur on a stroll are cemented in stone. (Credit: Scott Pearsons)

The tracks were created by a sub-adult T. rex or Nanotyrannus lancensis, and could help shed light on whether it was a ferocious athlete, as depicted in the iconic Jurassic Park car chase scene, or more of a slow-and-steady kind of hunter.

The largest footprint measured 18.5 inches long and 14.5 inches wide, which indicated belonged to a hefty animal. Further, the print also included three forward-facing toes and a rear-facing toe, much like a modern bird. These combined features allowed researchers to determine the track belonged to a large theropod, and T. rex is the only one known that lived during that time and locality.

Based on the position of the trackways, it was clear that the animal was enjoying a brisk walk at the time. Based on the distance between the footprints and estimates of its hip height — calculated from similar-sized museum specimens — the pace T. rex was moving when it created them could be calculated.

A Brisk Walk

The researchers estimated the walking speed of the T. rex to be 2.7 to 5 mph, which is much slower than, say, Usain Bolt, who clocks in a maximum sprinting speed of 27.3 mph. For context, the average walking speed for a human hovers around 3 mph. The calculated speed indicates T. rex was traveling at a slow trot, and at a speed similar to other large carnivorous dinosaurs. Still, even when walking, tyrannosaurs moved covered more ground in a single step than the large herbivores that they coexisted with and presumably hunted. Researchers published their Glenrock trackway findings in the journal Cretaceous Research.

But how does this fit with previous estimates of T. rex speed, based on other lines of evidence? Tony Martin, a trace fossil expert and professor at Emory University and unaffiliated with the study, said the new findings are in line with past estimates.

“Biomechanical studies of tyrannosaur bones, combined with calculations of their musculature and computer models, tell us that tyrannosaurs were more suited for walking and probably could not outrun, say, a jeep,” says Martin.

Converging Evidence

The track record seems to be converging on the same results researchers get from models using computer simulations.

“Although that might sound boring, it’s actually quite exciting, because it helps us more accurately visualize tyrannosaurs as real, living animals in their ecosystems about 70 million years ago,” says Martin.

But these trackways actually do very little to tell us about the hunting behavior of T. rex, as they could simply represent an everyday activity like strolling down the beach. In spite of this, Martin believes these trackways will be of great value for future discoveries and investigations of T. rex.

“These tracks will help paleontologists more easily recognize other tyrannosaur tracks that are out there, just waiting to be discovered,” says Martin. “Once identified, at least a few of those tracks should give us more clues about whether or not young tyrannosaurs constituted a Cretaceous teen hunger force.”

Based on the evidence, it seems like anyone in decent shape could’ve outrun a T. rex.

“Would I have challenged T. rex to a race, just to see how fast it could go? Probably not,” Martin added.

CATEGORIZED UNDER: Living World, top posts
MORE ABOUT: dinosaurs, paleontology
  • Keith Morse

    I don’t have to outrun the Tyrannosaur. I just have to outrun the other guy the Tyrannosaur is chasing.

    • outpost

      Would you leave me, a one-legged man with a slight limp carrying raw beef?

      • disqus_atlq8Zmtsd

        You just have to outrun the raw beef…. if only there was a way to put it down!

    • Mike Richardson

      That works for bears, but probably not as much for something that wouldn’t need to break stride to reach down, snag the other guy, and swallow him in one bite while continuing to pursue you. So in case someone ever gets the bright idea to genetically reconstruct a T-rex, let’s hope that the thing was a slower moving scavenger.

  • OWilson

    With a set of jaws like that, obviously our Tyranny was a meat eating carnivore.

    Carnivore’s tend to run faster than their prey, they have to!

    So no, it is highly unlikely that you could outrun them.

    • Bobby J

      We weren’t their prey, genius. Read the article. They estimated the T-Rex was eating the giant leaf eaters that moved… really slowly.

      • OWilson

        My point, dumbo, was that they were as fast as they needed to be to catch a meal.

        They are trying to figure out how fast T-Rex actually moved.

        If you know exactly how fast their prey moved, you should send that in. It would be useful :)

        • WKACH

          Elephants at their fastest are still a bit slower than humans, and they can’t maintain that for nearly as long.

  • John Do’h

    Tyrannosaur would not evolve to be so massive if speed was an issue. You are big to either… 1) attack bigger prey or… 2) scare/fight off competition. T. rex either attacked big slow dinos that others couldn’t kill or simply stole prey from smaller predators. Has anyone ever had the theory that T. rex was simply a bully thief that scared off smaller dinos and stole the meat? Dominant mammal predators are not too proud to steal if they can… it’s easier. T. rex wouldn’t even have bothered to chase a human, unless it was starving.

  • JonFrum

    So if, some day, scientists find footprints of me walking across a muddy shore in stone, will that tell them how fast I was able to run?

  • Bernie Sanders

    I miss the T-Rex I had when I was a kid.

  • martynW

    I think the key is which of us can corner faster. You don’t need to outrun something you can outmaneuver.

    • WKACH

      Not always true when the predator is so big.

  • Moshe Ben Avram

    See below post.

  • JustMike

    question may be for how long could you outrun T. Rex?

  • Terenc Blakely

    You don’t try to outrun it, you out maneuver it. Especially if you can dodge around some big trees. Not like I’d like to try of course. 😛

  • Brett_Bellmore

    I don’t have to outrun the T Rex. The T Rex has to outrun the bullets.

  • Galileo2

    Yes, I could outrun one. Because the moment a T-Rex would try to run in the Earth’s present gravity, his legs would snap like twigs.

    • WKACH

      Earth’s gravity hasn’t really changed significantly. Maybe you mean oxygen content?

      • Galileo2

        Nope. The Earth’s gravity would have had to be reduced.

        If the T-Rex tried to run in 1G at the speeds we know he did, his legs would snap like twigs.

        • WKACH

          Seriously, no. Earth’s mass has not changed on any meaningful scale from then to now, and even if it’s possible that Earth’s radius has changed, the amount of change that would be involved to make the type of huge difference you’re talking about is simply not realistically possible. It might account for gravity being marginally stronger, but not enough to make the legs of a T-Rex “Snap like twigs” or even enough to really make a difference that the creature would notice. Even those marginal differences are rooted in speculation, and there is not actual scientific evidence to support it.

  • Roderick Reilly

    Estimating the running/charging speed of a two legged predatory animal from its walking stride is ludicrous. Large wild animals ALWAYS surprise us with the speed of their short charging bursts. Also, keep in mind how very wrong earlier paleontologists were about the physiology of dinosaurs. The notions proposed above are probably overly conservative.


    It also would kind of depend on the context. There’s some debate about the actual oxygen levels toward the end of the Cretaceous period, with it being generally accepted that levels were relatively high, even higher than today. Some have recently argued against this conclusion based on more recent analysis of amber, but if it holds true that late Cretaceous oxygen levels were notably higher than today, then a T. Rex dropped into the modern world would lose quite a bit of speed, stamina, and endurance. Conversely, a human dropped into the late cretaceous period would likely find him/herself putting up substantially better run times. Also, being mammal and smaller, I have a lot more faith in our stamina/endurance to begin with. So I like my chances, unless you tell me this thing would be capable unbelievably fantastic sprinting (30+ mph) or excellent stamina (wear me out over quarter-mile to a mile). However, if it turns out that oxygen levels were actually lower than today, as some now suggest (which would make the giantism of the period’s fauna much more confusing), then I’d be a bit more worried.

  • VladTepesDracul

    I wonder what kind of gun it would take to bring one down? Probably nothing whose recoil any human could handle. Probably the best bet would be some kind of wire guided missile like the type used against airplanes.


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